Kevin L. Polk (Author)
Kevin L. Polk, PhD, is a clinical psychologist who has been a practicing for twenty-three years, primarily helping veterans and others with troubling trauma memories. For the past eight years, he has dedicated himself to the study of acceptance and commitment therapy (ACT), spending close to 20,000 hours studying the philosophy and theory behind ACT, and learning and designing ACT interventions. He is a peer-reviewed ACT trainer who is passionate about teaching others how to use the matrix to increase psychological flexibility and valued living. Find out more at [...]

Benjamin Schoendorff (Author)
Benjamin Schoendorff, MA, MSc, is a clinical psychologist with a passion for disseminating contextual psychotherapies. He is the author of two French language books, an ACT self-help book, and a clinician's manual based on the matrix diagram. A peer-reviewed acceptance and commitment therapy (ACT) trainer, he leads international workshops on integrating ACT and relationship-focused functional analytic psychotherapy through the use of the Matrix.

Mark Webster (Author)
Mark Webster is a registered psychotherapist with the United Kingdom Council for Psychotherapy (UKCP). Following a first career in the computer industry, he worked for ten years at a specialist personality disorder clinic in the National Health Service (NHS). His involvement in third-wave cognitive behavioral therapy (CBT) began with dialectical behavior therapy (DBT) in 1997, which led to an early interest in acceptance and commitment therapy (ACT). Webster has been an ACT trainer since 2002 and currently runs his own business specializing in acceptance and mindfulness therapies. In 2005, he founded the ACT special interest group within the British Association for Behavioural and Cognitive Psychotherapies (BABCP). In 2008, with Kevin Polk he created the ACT Matrix, a very user-friendly way of delivering ACT in a group setting. Webster's main interest is in finding ways to make ACT more widely available outside of traditional mental health settings. He has recently founded a community interest company called ACT Peer Recovery CIC to develop peer recovery in addiction and mental health. In addition to offering training in mental health, he regularly conducts ACT workshops for physical health practitioners, including nurses, physiotherapists, and occupational therapists. Webster has been practicing mindfulness for over twenty-five years and is current chair of the UKCP's Cognitive Psychotherapies College.

Fabian O. Olaz (Author)
Fabian Olaz, PsyD, is adjunct professor in clinical psychology and psychotherapies, and researcher and director of the Interpersonal Behavior Laboratory in the Faculty of Psychology, University of Córdoba (Argentina). He is an acceptance and commitment therapy (ACT) and functional analytic psychotherapy supervisor and psychotherapist at the Integral Center of Contextual Psychotherapy (CIPCO), and a recognized trainer in Argentina, Brazil and other South American countries.